Very nice collection. Always like the older stuff. My 'home-office' (where my books, desk and PC etc. are) is stuffed, as well as my attic. When I first step into it, you smell the books...
I think I have about 10 shelves (of 1.20 meter per shelf wide) full is f I do not 'compress' my boxed sets (I stuff them with other related products), 8 shelves full as things are now, most of it in older editions. My 3/3.5 edition stuff is about 1 and a half shelves worth of stuff, going on 2 (have some amazon orders in the mail with +/- 20 books).
The most room gets taken by 2nd edition stuff (all planescape, all spelljammer, all dark sun, lots FR, all GH, some DL, lots Ravenloft)
1.5 shelves with dragon and dungeon mags (a few from pre 100 dragon, plenty between 100 and 250, then again pretty much all as of 3rd ed, for dungeon, pretty much all as of 3rd ed)
1 shelf with basic DnD (all boxes, all modules, compendium and the thunder rift stuff, the acccessories, the gazetteers the mystara stuff).
1st edition, prolly almost one shelf (all the HC, all the modules)
Right now, most of it is stuffed and compressed onto 5 shelves and 4 'stacks' piled on top of 'formerly free space'.
That's what you get when you just can't say no to shiny new toys...